# -*- coding: utf-8 -*-
"""
# @Time    : 2022/11/7 21:46
# @Author  : Youngson
# @File    : Day1
# @Software: PyCharm
# @Desc    : 
"""

def evaluate(cj):
    cj = int(cj)
    if cj >= 90 and cj <= 100:
        print('A')
    elif cj >= 80 and cj <= 89:
        print('B')
    elif cj >= 60 and cj <= 79:
        print('C')
    elif cj >= 40 and cj <= 59:
        print('D')
    elif cj >= 0 and cj <= 39:
        print('E')

if __name__ == '__main__':
    while 1:
        cj = input("请输入分数:")
        evaluate(cj)
